1. Field of the Invention
The present invention relates to a crime prevention monitor system which monitors, on a remote control basis, the presence or absence of an illegal intruder entering into a monitor region to be monitored, such as an office, a shop, a school, a bank or a factory, on the basis of a picture signal received from a monitor camera installed in the monitor region for photographing the intruder.
2. Description of the Related Art
There has been so far well known such a sort of crime prevention system that a thermal radiation sensor or an infrared ray sensor is previously set in a monitor region to be watched so that when an intruder entering into the monitor region is detected by the sensor, the presence of the intruder is automatically reported to a concentrator installed in a security company and the like through a public line or a private line. With such a system, a guard of the security company rushes to the monitor region in question on the basis of the automatic report to the concentrator and when recognizing the abnormality on the spot, he or she quickly informs such a predetermined organization as a police station or a fire station of the abnormality.
The aforementioned crime prevention sensor and concentrator are usually interconnected by means of a transmitter which has a function of automatically calling the public or private line and by means of a receiver which enables communication of the transmission line in response to the calling of the transmitter through the line and sends a report signal received thereafter to the concentrator. When the crime prevention sensor detects the intruder entering into the monitor region, the following procedure is carried out and an automatic report to the concentrator is realized.
(1) The transmitter is started on the basis of an intruder detection signal received from the crime prevention sensor.
(2) The started transmitter automatically calls the receiver installed in the security company or the like.
(3) This results in the transmission line connected between the transmitter and the receiver being placed in its communication enable state.
(4) A predetermined report signal having identification data, etc. of the monitor region included therein is transmitted from the transmitter to the receiver.
(5) The transmitted report signal is demodulated at the receiver in a predetermined manner and then applied to the concentrator.
In this way, the prior art system can detect the presence or absence of the intruder entering into the monitor region accurately to a certain extent so long as the crime prevention sensor is high in detection accuracy. However, since the presence or absence of the intruder is judged only by the crime prevention sensor, when the intruder is one of authorized persons for the monitor region or when a mouse, a dog, a cat or a bird is detected as an intruder or when the aforementioned transmitter, receiver, etc. including the sensor are erroneously operated, for example, the system issues an erroneous report signal with a very low reliability. As a result, even when the above report is issued through a so-called terminal apparatus including the crime prevention sensor and transmitter disposed in the monitor region, the guard cannot determine that the report is actually correct until he rushes to the on-site monitor region and actually confirms the situation.
Further, with such a system, even when the above report is correct, the guard must confirm the on-spot situation, which inevitably requires a time loss until confirmation of the situation.
There has been recently proposed a crime prevention monitor system which can cope with such a situation as to require emergent confirmation with an improved reliability, and in which a monitor camera such as an industrial television (ITV) camera, is also installed in a monitor region to be guarded so that a picture signal from the monitor camera and the aforementioned report signal are transmitted from a terminal apparatus to a concentrator, whereby a watchman on at the concentrator can monitor the received picture image on a suitable display unit and can confirm the on-spot situation substantially on a real time basis. This crime prevention monitor system, however, has been disadvantageous in that it is hard for the watchman to judge whether or not the intruder into the monitor region is one of authorized persons therefor in actual situations because he usually cannot know substantially all information of the monitor region, which means that such a picture image is not effectively utilized.
As the number of terminal apparatuses increases not only the intruder detection and report accuracy of the crime prevention monitor system; but also its reliability; becomes very vital.